It can be desirable to determine the characteristics such as the density and/or thermal resistance (R-value) of gas-permeable materials including, for example, thermal and/or sound insulation materials for use in a residential and/or commercial building. Generally, various known methods exist for measuring the density and/or R-value of a material. Some known methods require the removal of a sample of the material from its installed, preferred location and/or the destruction of such sample in order to determine the density and/or R-value thereof. Some known methods do not provide a density and/or R-value measurement that is substantially representative of a large portion of the material or the entire material, and only provide an accurate measurement of a relatively small portion of the material.
A thermal and/or sound insulation product can be formed by blowing insulation material such as fiberglass and an adhesive onto a surface, and curing the applied materials. This method can be used in the formation of, for example, insulation product between wall studs and/or ceiling/floor joists. Methods and systems for forming such an insulation product are discussed in, for example, U.S. Pat. Nos. 4,712,347, 5,287,674 and 5,641,368. The density and/or R-value of such “blown-in” insulation products can depend on the specific manner in which such product is applied on-site. Accordingly, it can be desirable to determine whether such blown-in products meet certain density and/or R-value specifications.
It also can be desirable to measure the density and/or R-value of a gas-permeable material by non-destructive means, and/or without the need for removing such material from its preferred, installed location.
A known method for measuring the density and/or R-value of a gas-permeable material involves using a device which measures the airflow resistance through the gas-permeable material. From an experimentally-derived correlation between airflow resistance, density and R-value, the density and/or R-value can be calculated.